This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Rectal probe electro-ejaculation of male baboons has proven reliable for producing fresh, high quality sperm samples for investigative use in assisted reproductive technologies (ART) studies. In order to obtain baboon sperm samples for developmental reproductive studies and stem cell research, assigned male baboons provided semen samples via rectal probe electro-ejaculation for sperm isolation. Five identified areas for the use of baboon sperm include: 1. In vitro fertilizations of oocytes collected via follicular aspirations from hormonally stimulated female baboons. (Sperm required day of aspiration procedures;intra-species fertilizations) 2. In vitro fertilizations of oocytes from unplanned necropsy ovaries. (Sperm required 48hr from oocyte isolations on necropsy date;intra &inter-species fertilizations) 3. Alternative sperm source for fertilization studies in either macaques (rhesus;cynomolgus) or chimpanzee oocytes when neither macaque nor chimpanzee sperm is unattainable on day of oocyte retrieval. (Sperm required day of oocyte collections;inter-species fertilizations) 4. Cryopreservation and banking of sperm in liquid nitrogen. 5. Fresh sperm collections for research investigations (i.e. testing new antibodies [immunocytochemistry];biochemistry studies;etc). The requested baboons will be allowed rest periods between ejaculation procedures as mandated by the current facility standard operating procedure and monitored by a veterinarian. For males that successfully produce stem cell lines, we may request 2-3 skin samples (~5mm biopsy punch), 3-5mls of whole blood in clot tube and/or 3-5mls of whole blood in EDTA tube for genotyping or other genetic comparisons between the male and the established cell lines.